: The goal of this work is to elucidate the relationship between neural activity in auditory cortex and sound perception. The applicant will determine 1) the abilities of humans and nonhuman primates to perceive and integrate spectral and temporal features of sounds, and 2) the relationship of single neuron responses in auditory cortex to psychophysical performance. For Aim 1, human and nonhuman subjects will be trained to discriminate sounds that vary along temporal or spectral dimensions, and for Aim 2, neurons will be recorded in nonhuman primate auditory cortex during behavioral discriminations. Signal detection methods will be used to determine the discriminative capabilities of single neurons, and whether their firing is more closely associated with the physical attributes of sound or the higher level decision to respond to the sound. The data will provide information for understanding the effects of cortical disruptions, as well as basic understanding of temporal acoustic processing. The results are of potential use for treating stroke and dyslexia.